The study had as
objective to evaluate the resting energy expenditure (REE) of post-menopause
women submitted to a training program with weights. Thirty women, age between
45 and 70 years (FSH > 40 mIUmL), separated in two groups (TG: training n
= 15 and CG: control n = 15) were studied. The body mass index (kg/m2)
was calculated and the body fat percentage and the muscular mass were determined
through bioelectric impedance (BIA). The REE was obtained through indirect calorimetry
(respiratory O2 and CO2) and calculated by the Weir equation.
The measurement occurred after 12 hours of fasting, during 30 minutes under
controlled temperature and humidity. The TG participated of the training program
with weights during 16 weeks, in the frequency of three times per week. The
analyzed data by the t-Student, Mann-Whitney and ANOVA tests (p < 0.05) demonstrated
that the TG had body mass increased in the 1.8 kg mean, muscular mass in 2.0
kg and the REE presented increase of 8.4% in relation to the CG. In conclusion,
the training with weights increased muscular mass and REE. Therefore, this kind
of exercise is recommended part of strategy to revert muscular and metabolic
losses derived from aging and/or menopause.

Keywords:
Menopause. Exercise. Resting energy expenditure.

INTRODUCTION

Several physiological
alterations which occur in women during aging increase with menopause. Among
them, the main are: representative decrease of female sexual hormones; increase
of adiposity; reduction of muscular mass and decrease of resting energy expenditure.
Consequently, there is a reduction of mobility and balance as well as an increase
of risk of falls, decreasing hence, life quality as age progresses(1-2).

It is possible
that the decrease of the metabolically active lean tissue reduces the energetic
needs in resting and that this fact associated with the decrease of physical
activity with no proportional reduction in caloric ingestion, causes an accumulation
of body fat(3-4).

On the other hand,
many studies have shown the importance of weight training in physical fitness
programs, once they stimulate the increase of muscular mass which increases
the resting energy expenditure due to the straight relationship which exists
among these factors(5).

Physical exercise,
which includes muscular strengthening exercises, could minimize the risks and
even revert losses faced with aging, especially at menopause(6-7).
Within this context, the aim of the present study was to evaluate the effect
of weight training over the resting energy expenditure of post-menopause women.

MATERIAL

Subjects:
Thirty post-menopause women, age 45-70 years, with over one year of menstruation
interruption (FSH values higher than 40 mIU/mL), and sedentary, followed by
the Center of Metabolism in Exercise and Nutrition (CeMENutri) and by the Climacterium
and Menopause Nursing Room of the Clinics Hospital, Medicine School of Botucatu
 ENESP, were part of the study group. All of them were informed about
the study's proposal as well as the procedures to be performed and signed a
free and clarified consent form according to Resolution Nº 196 from 10 October,
1996 of the Ethics in Research Committee (CEP) of the Medicine School 
UNESP  Botucatu. The favorable answer from the CEP was given on April
05, 2004. All subjects went through a medical triage in order to verify the
inclusion criteria in the study. Therefore, women who underwent hormonal replacement
therapy; were smokers; made use of alcohol; performed physical exercises; made
use of vitamin supplements and/or minerals or had any type of endocrine-metabolic,
gynecological and/or osteo-articular diseases which could hamper weight exercises
practice were excluded. They were separated in two groups: (TG: Training
and CG: Control). There was no diet prescription and the women were instructed
to continue their eating habits.

Weight training
protocol: It was prescribed and supervised by physical education professors
and had the duration of 16 weeks, in which the 4 first weeks were scheduled
for physical fitness leveling. All loads were individually measured for each
exercise in the end of the first 4 weeks, through a 1RM test(8).
The progression for the determined aim was gradual until it reached 3 sets of
8-12 maximal repetitions with 60-80%(9), keeping the intensity/volume
ratio steady, that is, the higher the volume, the lower the intensity and vice-versa.
These loads suffered periodical readjustments with the purpose to generate progressive
overload and training break of the homeostasis.

The training protocol
was adapted to women above 45 years of age, involving weight exercises aiming
hypertrophy, with a program of 3 weekly sessions. Ten exercises were performed:
2 for the chest, 2 for the back, 3 for the thighs, 1 for the biceps and 1 for
the triceps. The exception was the abdomen with 1 exercise including 3 sets
of 30 repetitions. The exercises were performed in the following order: leg
press, knee extension, knee flexion, bench press, peck deck, row, high pull,
triceps pulley, biceps curls and abdominal.

The recovery interval
was of 2 minutes, both between sets and exercises. One minute rest between sets
was given in the exception. Moreover, the women were oriented to perform the
eccentric action in 2 seconds and the concentric action in 1 second. The breathing
was controlled so that expiration should be performed in the concentric action
and inspiration in the eccentric action of the exercise with the purpose to
avoid apnea.

Body composition
evaluation: Body mass was evaluated (kg) using a platform type anthropometric
scale (Filizola®, Brazil), with 0.1 kg precision and capacity
of up to 150 kg., and height (m) through a 0.1 cm precision portable anthropometer
(SEKA®) which was attached to the wall. Both measurements were
conducted according too procedures described by Gordon et al.(10).
The body mass index (BMI) was calculated through the body mass (kg)/height (m)
ratio2 and classified according to standardization of the World Health
Organization(11). The measurement of the waist circumference (WC)
was also checked with inextensible measuring tape(12).

Muscular mass 
MM (kg) and body fat percentage were measured through bioelectric impendence
 BIA (BIODYNAMICS model 450), according to equations proposed by Janssen(13)
and Segal(14) respectively. Afterwards, the percentage of the muscular
mass  MM (%) in relation to the body mass was calculated.

Laboratory evaluation:
In the beginning of the study, the follicle stimulating hormone (FSH)(15),
was dosed by the automatic analyzer Elecsys® 2010 (Roche Diagnostics®,
Mannheim, Germany) in order to confirm menopause and specific kit for immune
essay through electrochemiluminescence in solid phase.

Resting energy
expenditure evaluation (REE): The participants were previously instructed
about the evaluation. They should not perform physical exercises, ingest coffee,
black tea or alcohol 24 hours prior to the test, and, in the morning of the
evaluation day, they should be at 12-hour fasting. The individuals were in dorsal
decubitus position on a stretcher in a thermo-neutral environment 23-24°C
and 40-60% of relative air humidity. They should remain quiet, comfortable (avoiding
movement) and not sleeping. The oxygen intake was obtained (O2) and
the carbon dioxide gas production (CO2) continuously for 30 seconds.
The 10 first minutes were discarded for the calculation in order to guarantee
higher data homogeneity. The resting energy expenditure (REE) was calculated
through the equation proposed by Weir(16) by open circuit indirect
calorimetry through the mixing-chamber system, in a Quinton equipment (QMC).

During the entire
measurement of the REE the heart rate was monitored (HR) through Polar frequencymeter
(model A1) obtaining thus the interval mean. The RQ  respiratory quotient
was calculated by dividing the produced carbon oxide gas (CO2) by
the intaken oxygen (O2), in order to know the resting energy
substrate.

Study's framework:
The study had total duration of 20 weeks (M0-M1), divided as following: the
two anterior and the two posterior weeks served for the evaluations, the weight
exercises protocol (M0-M1) had the duration of 16 weeks. The evaluation of the
maximal load by 1RM test was exception, once it was performed in the end of
the 4 weeks of the training protocol.

Statistical
analysis: T-Student test was used for data analysis in the comparison between
the training (TG) and control (CG) groups, considering variables with normal
distribution, and the Mann Whitney test, in the lack of normality(17).
The comparisons of the groups in the two moments of the study (M0  initial
and M1  final) were performed from the variance analysis technique for
the model of repeated measures in two independent groups(17). The
ratio between muscular mass and the resting energy expenditure (REE) was obtained
through linear regression. All discussions occurred with 5% of significance
level.

RESULTS

No statistically
significant difference (p > 0.05) was found in the comparison between groups
at the initial moment of the study (M0), showing thus homogeneity (table
1). The women of both groups were classified as sarcopenic, with abdominal
and sarcopenic adiposity. Moreover, all of them had follicle stimulating hormone
levels (FSH) higher than 40 mIU/mL, showing post-menopause state.

As well as in the
general characteristics at the initial moment (M0) of the study, none significant
difference was found in the indicators of the body composition, when the training
(TG) and control (CG) groups were compared. However, during the study (M0-M1),
there was significant increase (p < 0.05) for the variables: body
mass (1.8 kg corresponding to 2.6%), muscular mass (2.0 kg corresponding to
10.6%) for the training group (TG), with no alterations in the body fat buildups
and distribution (figure 1).

Figure
2 shows increase of 110 kcal (8.4%) in resting energy expenditure (REE)
of the training group (TG) and reduction of this component at around 70 kcal
(4.9%) in the control group (CG), with significant difference (p <
0.05) in the comparison between groups during the time (M0-M1). Nevertheless,
no significant difference was observed in heart rate (HR) and in the oxidation
of energy substrates represented by the respiratory quotient (RQ).

The linear regression
between the resting energy expenditure (REE) and the muscular mass is presented
in figure 3. The association was positive and significant
(R2 = 0.55 and p < 0.05).

DISCUSSION

Muscular mass loss
(senile sarcopenia) is one of the changes derived from the hormonal alterations
which occur with aging(18). Nonetheless, the mechanisms of the female
sexual hormones action over the muscular mass, if existing, are still obscure(19).

The women of this
study, both of the training (TG) and the control groups (CG), were considered
sarcopenic at the initial moment (M0). Muscular mass percentage values were
below the recommendation of 28% for women(20), presenting 27.8 ±
3.6% and 27.3 ± 2.9% of body mass in the training and control groups,
respectively. However, in the group submitted to the 16 weeks of weight training,
reclassification of the percentage of muscular mass was observed (for 30.0 ±
3.7% of body mass).

Weight training,
among other factors, has been mentioned as having increased lean body mass and
even decreased body fat(21). Evans(22) emphasizes that
the processes through which this training stimulates muscular hypertrophy are
not well-established yet. Lifting weight requires that the muscle produces strength
(concentric-eccentric). This muscular work has been prescribed for producing
structural damage which can stimulate the muscular protein metabolism increase.
This muscular damage triggers a myriad of metabolic events similar to the acute
phase of the inflammatory response, which includes: activation of the complement
system; mobilization of neutrophiles; increase of interleucine-1 (IL-1) flow,
accumulation of muscular macrophage and increase of the muscular protein synthesis
and degradation.

Weight training
can be effective for adults and older subjects' health once it changes, among
other components, the energy expenditure which results from the combined influence
of expended energy with exercise, increase in resting energy expenditure as
well as increase of metabolic demand(23). Although the energy expenditure
during the weight exercises session was not big (about 150 to 200 kcal per session)(24),
during the recovery period (post-exercise), the oxygen consumption increased,
generating higher energy expenditure, known as EPOC (excess post-exercise oxygen
consumption)(25).

In this study,
after 16 weeks of weight training an increase in the resting energy expenditure
(REE) of 110 kcal/day (8.4%) was observed for the training group (TG); a value
statistically higher (p < 0.05) in comparison with the control group
(CG), which presented reduction of 70 kcal/day (4.9%) during the time (M0-M1).

There is evidence
that the resting energy expenditure increase may be estimated by the increase
of approximately 100 to 150 kcal/day in the daily energy expenditure(26).
Studies suggest an increase of 6.8 to 7.7% in the resting energy expenditure
after 12 to 16 weeks of weight training in adults and older individuals(27-28).
Ballor and Poehlman(29) observed in meta-analysis that the resting
energy expenditure seems to be proportional to the metabolic active tissue.
It is believed that for each kilogram of lean mass an increase of around 50
kcal in the daily energy expenditure occurs, and that in sedentary individuals
the muscular mass is one of the main determinants of the resting energy expenditure(30-31).

Evidence on these
findings were identified in this study which shows a positive (R2
= 0.55) and significant (p < 0.05) relationship between muscular mass
and the resting energy expenditure (REE). However, the explanations for the
increase in the total and resting energy expenditure can also be related, besides
the muscular mass increase, to the exercise intensity, to the increase in the
metabolic activity of the lean tissue as well as to the increase in the basal
concentrations of noradrenaline(23,27).

Continuous exercise
practice promotes adaptations in the metabolism of fats which enable the trained
body to choose the use of this substrate as energy source, over carbohydrates(26).
Nevertheless, the extension of this effect for the resting conditions is still
controversial.

Respiratory quotient
values (RQ) enable the evaluation of the use of the energy substrates by the
body in different situations such as in resting and exercise. In this study,
the values of the RQ were similar, in average 0.82 both in the training (TG)
and control groups (CG), and no significant change (p > 0.05) in this concern
was evidenced after the 16 weeks of weight training.

In the study by
Nadai et al.(32), aerobic training alone was not sufficient
to promote changes in the body fat and muscular mass of post-menopause women.
Nonetheless, when the training intensity was increased by the addition of weight
exercises, a reduction in the general adiposity associated with the increase
of muscular mass was seen. However, long periods of training seem to be necessary,
around 25 weeks, in order to see it happening(33).

It is believed
that the maintenance of muscular mass may help to avoid the decrease of the
metabolic rate, keep the maintenance of the body weight as well as prevent visceral
adiposity(34). In this context, weight training seems to be effective
and safe, and should be therefore, prescribed as auxiliary in physical exercise
trainings which aim to control the body weight of adult and older individuals(23).

CONCLUSION

Post-menopause,
sedentary women, when submitted to a 16-week weight training protocol aiming
hypertrophy, showed: modifications in the indicators of the body composition
related with increase of the lean mass (muscular and fat-free mass), with no
modifications in adiposity; increase of the resting energy expenditure positively
related with the muscular mass, with no significant alteration of the respiratory
quotient (types of oxidized energy substrates). Therefore, weight training is
suggested as an economical and safe choice for the improvement of these women
since it reverts, or at least, attenuates organic and metabolic consequences
menopause-related. It also rescues functional abilities and promotes life quality.
Moreover, the control of food ingestion and longer training time may be needed
in order to intensify results such as muscular mass increase and even reduction
of body adiposity.

ACKNOWLEDGMENTS

To Professor Dr.
Carlos Roberto Padovani and GAP (Group of Research Aid) for the statistical
analyses;

To the colleagues
Fabrício César de Paula Ravagnani and Okeslei Teixeira for the
great contribution in the evaluation of the resting energy expenditure (REE);

To the Coordination
of Personnel Improvement of Higher Level (CAPES) for the Master's Research Scholarship;

To the Foundation
of Research Aid of the São Paulo State  FAPESP for the Research
Aid.